Determine how many solutions exist for the system of equations. ${-6x+y = -9}$ ${-3x-3y = -3}$
Answer: Convert both equations to slope-intercept form: ${-6x+y = -9}$ $-6x{+6x} + y = -9{+6x}$ $y = -9+6x$ ${y = 6x-9}$ ${-3x-3y = -3}$ $-3x{+3x} - 3y = -3{+3x}$ $-3y = -3+3x$ $y = 1-x$ ${y = -x+1}$ Just by looking at both equations in slope-intercept form, what can you determine? ${y = 6x-9}$ ${y = -x+1}$ The linear equations have different slopes. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ When two equations have different slopes, the lines will intersect once with one solution.